Relating cardiorespiratory responses to work rate during incremental ramp exercise on treadmill in children and adolescents: sex and age differences

Abstract

Purpose Evaluation of cardiopulmonary exercise testing (CPET) slopes such as $$d\mathrm{H}\mathrm{R}/d{\mathrm{W}\mathrm{R}}_{\mathrm{t}\mathrm{o}\mathrm{t}}$$ d H R / d W R t o t (cardiac/skeletal muscle function) and $${d \dot{V}{\text{O}} }_{2}/d{\mathrm{W}\mathrm{R}}_{\mathrm{t}\mathrm{o}\mathrm{t}}$$ d V ˙ O 2 / d W R t o t (O2 delivery/utilization), using treadmill protocols is limited because the difficulties in measuring the total work rate ($${\mathrm{W}\mathrm{R}}_{\mathrm{t}\mathrm{o}\mathrm{t}}$$ W R t o t ). To overcome this limitation, we proposed a new method in quantifying $${\mathrm{W}\mathrm{R}}_{\mathrm{t}\mathrm{o}\mathrm{t}}$$ W R t o t to determine CPET slopes. Methods CPET’s were performed by healthy patients, (n = 674, 9–18 year) 300 female (F) and 374 male (M), using an incremental ramp protocol on a treadmill. For this protocol, a quantitative relationship based on biomechanical principles of human locomotion, was used to quantify the $${\mathrm{W}\mathrm{R}}_{\mathrm{t}\mathrm{o}\mathrm{t}}$$ W R t o t of the subject. CPET slopes were determined by linear regression of the data recorded until the gas exchange threshold occurred. Results The method to estimate $${\mathrm{W}\mathrm{R}}_{\mathrm{t}\mathrm{o}\mathrm{t}}$$ W R t o t was substantiated by verifying that: $$d{ \dot{V}{\text{O}} }_{2}/d{\mathrm{W}\mathrm{R}}_{\mathrm{t}\mathrm{o}\mathrm{t}}$$ d V ˙ O 2 / d W R t o t for treadmill exercise corresponded to an efficiency of muscular work similar to that of cycle ergometer; $$d{ \dot{V}{\text{O}} }_{2}/d{\mathrm{W}\mathrm{R}}_{\mathrm{t}\mathrm{o}\mathrm{t}}$$ d V ˙ O 2 / d W R t o t (mL min−1 W−1) was invariant with age and greater in M than F older than 12 years old (13–14 years: 9.6 ± 1.5(F) vs. 10.5 ± 1.8(M); 15–16 years: 9.7 ± 1.7(F) vs. 10.6 ± 2.2(M); 17–18 years: 9.6 ± 1.7(F) vs. 11.0 ± 2.3(M), p < 0.05); similar to cycle ergometer exercise, $$dHR/d{WR}_{tot}$$ d H R / d WR tot was inversely related to body weight (BW) (r = 0.71) or $$\dot{V}{\text{O}}_{{2,{\text{~peak}}}}$$ V ˙ O 2 , peak (r = 0.66) and $$d{ \dot{V}{\text{O}} }_{2}/d{\mathrm{W}\mathrm{R}}_{\mathrm{t}\mathrm{o}\mathrm{t}}$$ d V ˙ O 2 / d W R t o t was not related to BW (r = − 0.01), but had a weak relationship with $$\dot{V}{\text{O}}_{{2,{\text{~peak}}}}$$ V ˙ O 2 , peak (r = 0.28). Conclusion The proposed approach can be used to estimate $${\mathrm{W}\mathrm{R}}_{\mathrm{t}\mathrm{o}\mathrm{t}}$$ W R t o t and quantify CPET slopes derived from incremental ramp protocols at submaximal exercise intensities using the treadmill, like the cycle ergometer, to infer cardiovascular and metabolic function in both healthy and diseased states.

Health risks for children exercising in an air-polluted environment can be reduced by monitoring air quality with low-cost particle sensors

“…For example, Reybrouck et al 15 reported the V̇O 2max in boys aged 9–16 in the range of 50.6–56.6 mL O 2 min −1 kg −1 and in girls at the same age between 42.2 and 43.7 mL O 2 min −1 kg −1 . Similar values of V̇O 2max for the same age groups of children were recently reported by Lai et al 14 . These findings show that the values of V̇O 2max in children, expressed in relative values, are on a level similar to or even higher than healthy adults 22 – 24 .…”

“… Value calculated based on the data collected in a paper by Lai et al 14 (for comparisons, see also Reybrouck et al 15 ). …”

Exercise capacity and muscle strength in patients who have undergone the Fontan procedure: a retrospective follow-up study

“…In general, exercise capacity increases during physical growth and reaches its peak in early adulthood. 24,25 Therefore, this growth may lead to confusion in the interpretation of exercise capacity. In previous studies, a cardiopulmonary exercise test (CPET) was used in the assessment of exercise capacity and longer-term follow-up was performed.…”

Exercise capacity in a cohort of children with congenital heart disease

“…In children, the interpretation of CPET poses an additional challenge related to physical changes during growth [11]. In general, exercise capacity increases with growth to reach a maximum in early adulthood [12][13][14][15]. To avert confounding, there is a need to relate CPET parameters with metrics of growth.…”